2015-03-03T19:00:38ZDouglas-fir (Psuedotsuga menziesii) biomass and nutrient removal under varying harvest scenarios involving co-production of timber and feedstock for liquid biofuelshttp://hdl.handle.net/1957/54814
Douglas-fir (Psuedotsuga menziesii) biomass and nutrient removal under varying harvest scenarios involving co-production of timber and feedstock for liquid biofuels
Coons, Kristin L.
In this study an improved model of biomass and nutrient estimation of coastal Douglas-fir (Psuedotsuga menziesii) in the Pacific Northwest has been developed across a wide range of stand management regimes. This study quantifies and defines the type and intensity of biomass harvest and associated removal for actively managed stands on a scale applicable to biofuel production. This study provides a preliminary estimate of the implications of varying levels and intensity of harvest on long term site productivity that will require calibration with actual harvest and nutrient flux data. Of total tree mass over all sites, 1-yr-old, 2-yr-old, and ≥3-yr old foliage, live branches, bark, sapwood and heartwood comprised 2% (1.0-3.4% range), 1% (0.6-1.7% range), 1% (0.8-3.0% range), 3.3% (2.2-4.5% range), 13% (8-31% range), 44% (24-59% range) and 35% (24-44% range), respectively, of total aboveground tree biomass. Four scenarios for aboveground biomass removal from the site were considered: 1) BO: merchantable bole only; 2) BT: entire tree except for the top portion above a four-inch stem diameter; 3) VC: entire tree except for one vertical half of the crown; and 4) WT: whole tree with top and all
branches. The nutrient harvest and biomass removed under each scenario increased in the following order BO<BT<VC<WT. The mean relative total aboveground biomass removed by each of the scenarios was 70% for merchantable stem only (BO), 75% for loss of the top above the four inch stem diameter (BT), 97% if one vertical half of the crown was sheared off. Total foliage contained 20, 34 and 49% of Ca, Mn and N, respectively, despite comprising no more than an average of 9% of the total stand level aboveground biomass. The total aboveground nutrient pool contained no more than 2.2% (average of 0.4%) of the total pool (soil + aboveground biomass) of N, P, Ca, Mg and S, and contained no more than 8.6% (average of 1.4%) of the total site K pool. The maximum stability ratio among all nutrients and sites in this study was 0.089 (0.006 mean) and at a full rotation of 50 years would be no higher than 0.113 (0.0081mean), just over the static ratio threshold of slight risk to long term site productivity (0.1). These static stability ratios are limited in their estimates of potential adverse impacts on nutrient availability and supply because nutrient fluxes (e.g., mineralization, leaching and atmospheric deposition rates) are not taken into account. The quantification of nutrient fluxes is necessary to provide a more accurate representation of future impacts of increased harvesting intensity to long term site productivity.
Graduation date: 2015
2014-12-19T00:00:00ZClimbers' preferred management actions : addressing resource and crowding impacts in Yosemite Valleyhttp://hdl.handle.net/1957/54809
Climbers' preferred management actions : addressing resource and crowding impacts in Yosemite Valley
Burns, Molly T.
As more people become interested in rock climbing, the need to understand climbers and their preferences and how their activities impact the resource are more vital than ever. With increased use, and with little empirical data about the Yosemite climbing community, park managers cannot adequately develop a comprehensive climbing management plan. The objectives of this research are to use a theoretically based survey instrument to measure Yosemite NP climbers' level of support for different management strategies. I used chi-square analysis to evaluate the relationship between my independent variables, climbers' self identified skill level and dependent variables, climbers' perceived crowding and support for different resource and social based management actions. I found a relationship between climbers' experience level and their support for resource based management actions. This suggests to managers that managing climbing impacts, either resource based or social impacts, should focus on managing the resource by using restoration techniques, or providing signs or maps to direct climbers to climbing areas.
Graduation date: 2015
2014-12-04T00:00:00ZTreatment options for controlling Brachypodium sylvaticum and impacts on native vegetationhttp://hdl.handle.net/1957/54784
Treatment options for controlling Brachypodium sylvaticum and impacts on native vegetation
Fjeran, Taylor K.
Invasive vegetation control studies traditionally aim to control existing populations as well as limit future spread of the species. However, little additional attention has been dedicated to aiding native communities to recover and reestablish. One prominent example of a studied invasive is Brachypodium sylvaticum (Huds.) P. Beauv. (false brome), a bunchgrass native to Europe, Asia, and North Africa but invasive to North America. B. sylvaticum is capable of forming dense monocultures under forested canopies in North America. Such invasions can detrimentally affect the ecological functions and processes of an inhabited ecosystem. To address the negative ecological effects of this grass' invasion, this study evaluated how herbicide and prescribed burns, singly and in combination, affected B. sylvaticum abundance and the surrounding plant community in western Oregon foothills. The specific objectives of this study were to: 1) determine the most effective treatment in reducing B. sylvaticum abundance or cover in the field, 2) evaluate how different treatments alter total plant community cover, excluding B. sylvaticum, 3) assess residual seed bank following prescribed treatments, and 4) describe compositional changes in the plant communities after one growing season following control treatments.
My study was located in Oregon State University's McDonald Forest under a split-plot design with 12 blocks total and 10 treatments randomly assigned within each block, which included the use of two herbicides and prescribed burning in various combinations, for a total of 9 treatments and a no-treatment control. All treatments that involved application of an aggressive, broad-spectrum, foliar herbicide applied in the summer were most effective in reducing not only the existing B. sylvaticum in the field, but also the residual seed bank one year after application, while maintaining native community seed bank abundance. A prescribed burn following the aforementioned summer herbicide demonstrated no added benefit in controlling B. sylvaticum. Less intense fall prescribed burns without a previous broad-spectrum herbicide treatment may promote B. sylvaticum growth.
All treatments involving the aggressive summer herbicide displayed significant reductions in total native species cover and species richness compared to the controls. Treatments without this herbicide demonstrated richness and diversity similar to the controls, but the remaining species after one growing season were primarily dominant shrubs or non-native weeds. Using multivariate community analysis, I documented a shift in species composition due to treatment in which the strongest effect also associated with summer herbicide application.
This study now serves as a baseline to develop and refine cost-effective techniques for both controlling B. sylvaticum populations in the Oregon Coast Range and restoring invaded native plant communities. Future studies should monitor any responding B. sylvaticum populations and species composition beyond the first growing season, consider incorporating multiple applications of such treatments, and quantify seed recruitment by both B. sylvaticum and native species.
Graduation date: 2015
2014-12-05T00:00:00ZJudicial deference and its potential effect on agency science and natural resource managementhttp://hdl.handle.net/1957/54634
Judicial deference and its potential effect on agency science and natural resource management
Grisa, Amanda Marie Schenk
The USDA Forest Services' actions have come under greater scrutiny by a public that has become increasingly concerned with the legality of their actions. Often, challenges involve the quality of science used in the decision-making. Congress has mandated that the agency use the "best available science" in its decision making in various relevant environmental statutes and rules, like NEPA, ESA, NFMA, and its 2012 Forest Planning Rule. A question remains of how the judiciary will evaluate the use of science by the agency to analyze the impacts of its actions. The judiciary has developed various precedence to determine the appropriate level of deference, authorized by the APA§706, granted to the agency when determining the legality of these actions. An agency may be granted deference, or a yield judgment by the court, when analyzing its compliance with a rule or statute it administers. There are various types of deference that can be applied during the review of an agency action based on the type of action and the root of the claim, these include Chevron, Skidmore, Auer, and no deference. The judiciary has applied these precedence's that granted this deference to the Forest Service's actions inconsistently. Deference was high in the 1980s, but fell through the 1990s, and finally reaching an ultimate low in 2007. It is hypothesized that Lands Council v. McNair, 2008 (Lands Council III), a case focused on a project aimed at restoring the natural composition of the forest through various silvicultural techniques, has established Stare Decisis in that it returned a decision that established the judicial policy of agency review toward a standard of high deference. Through a case analysis of the methods of USDA Forest Service science and the reasoning of its use by the agency of 45 cases in the United States Court of Appeals for the Ninth Circuit, we have examined the importance of Lands Council III. This is seen in the realignment of the appellate and district court after the Lands Council III decision and the acceptance of the 2012 Forest Planning Rule, requiring a higher level of "best available science" towards a high level of deference to the USDA Forest Service. This is in regard to the science used to satisfy the requirements of the relevant environmental statutes and rules. The previous inconsistencies in review over time of the USDA Forest Service in the appellate court, and from the district court to the appellate court, have resulted in a lapse in the nexus of the law and science to allow for effective natural resource management and policy. The future policy implications after the result of Lands Council III and the 2012 Forest Planning Rule and the various levels of deference granted to the agency by the court are many, and can have varying affects on the way we produce science and manage our natural resources.
Graduation date: 2015; Access restricted to the OSU Community, at author's request, from Dec. 12, 2014 - June 12, 2015
2014-12-08T00:00:00Z